Coenzyme Q is an essential component which is distributed in a wide variety of living organisms ranging from bacteria to mammals. It is known that coenzyme Q undergoes oxidation/reduction cycles in living organisms and functions as an electron carrier in an electron transport system, and reduced coenzyme Q is an antioxidant. It is also known that in many animals including humans, fishes, and birds, coenzyme Q is mainly composed of coenzyme Q10 having 10 repeat structures in its side chain, and about 40% to 90% of coenzyme Q present in living organisms is generally in its reduced form. Since coenzyme Q can be synthesized in living organisms, coenzyme Q does not belong to the vitamin group, but it is thought to be substantially the same as vitamins. Also, the human ability of biosynthesis of coenzyme Q10 decreases with aging to decrease the coenzyme Q10 content in living organisms, and thus the need for supplying coenzyme Q10 in some form is demanded.
In coenzyme Q10 oxidized coenzyme Q10 is used as an agent for a congestive heart failure in medical applications. In addition to medical applications, oxidized coenzyme Q10 is used as a nutritional supplement or nutritional adjuvant like vitamins, or used for effectively treating an allergic disease or increasing athletic ability. Therefore, the effectiveness of oxidized coenzyme Q10 has been reported in a wide variety of fields. Furthermore, the effectiveness for brain diseases such as dementia, and the like has been reported, and it can thus be expected that oxidized coenzyme Q10 has high effectiveness for elderly persons.
In this way, coenzyme Q10 has high usefulness, and no toxicity is observed in a safety test using animals, in which coenzyme Q10 is continuously administered to rats for 52 weeks with a high dose of 1.2 g/kg/day. Therefore, the coenzyme Q10 is a compound proved to have high safety (J. Agric. Food Chem., 1999, Vol. 47, P3756-3763). However, coenzyme Q10 is only actually used as a skin agent other than oral administration, and thus has difficulties in practical administration to a patient with a serious disease, an elderly person or a young child who cannot easily orally intake coenzyme Q10. Furthermore, in a topical site such as the intestinal canal, the nose, or the ears, which are easily affected by an allergic disease, a sufficient concentration of coenzyme Q cannot be obtained by oral administration. Therefore, in fact, coenzyme Q cannot be effectively utilized.